You're looking in the wronn direction. The "Shake to Find" feature is used when you cannot find your mouse pointer. It is not intended to be used when you can locate the mouse pointer, but want to make others aware of its location.
In the comments you wrote that you specifically want this feature for making others aware of your mouse pointer location when screen sharing and similar. There's no way of making that feature do what you want.
Luckily, multiple utility apps exist for precisely this purpose:
You can go to the App Store and buy "Cursor Pro" by IXEAU UG, which works as a mouse pointer highlighter and magnifier when pressing a hot key.
Another alternative is the app "Mouseposé" from Boinx Software, which adds a spot light to your mouse pointer. It can also do other stuff such as adding an animation when you click the mouse. I haven't had any issues with stability with this program in its latest version.
A cheaper alternative is "myPoint Light S" from Code Race on the App Store, which allows you to add a visual effect to the mouse pointer by pressing a hot key.
Another alternative is the free program "Highlighter" which permanently adds a ring around your mouse pointer.
Another free program is "Mouse Locator" from 2point5fish, which allows you to trigger a sniper like graphics with a hot key. This app doesn't seem to be updated anymore, though - so even though it is free, it might not be worth the extra effort.